HRSA develops shortage designation criteria and uses them to decide whether or not a geographic area, population group or facility is a Health Professional Shortage Area or a Medically Underserved Area or Population.

Programs that use HPSAs to determine eligibility may utilize the HPSA data as of a certain date in time in order to facilitate program operations. To locate NHSC approved sites with eligible HPSAs and the corresponding HPSA scores for use in the National Health Service Corps programs, individuals should refer to the NHSC Jobs Center. Find HPSAs, MUAs and MUPs by state, county or street address.

Please note: not all programs that use the HPSA or MUA/MUP designation to determine eligibility use them in the same way. The National Health Service Corps uses HPSA data as of a certain date.

HPSAs may be designated as having a shortage of primary medical care, dental or mental health providers. They may be urban or rural areas, population groups or medical or other public facilities.

As of June 19, 2014:

There are currently approximately 6,100 designated Primary Care HPSAs. Primary Care HPSAs are based on a physician to population ratio of 1:3,500. In other words, when there are 3,500 or more people per primary care physician, an area is eligible to be designated as a primary care HPSA. Applying this formula, it would take approximately 8,200 additional primary care physicians to eliminate the current primary care HPSA designations. While the 1:3,500 ratio has been a long standing ratio used to identify high need areas, it is important to note that there is no generally accepted ratio of physician to population ratio. Furthermore, primary care needs of an individual community will vary by a number of factors such as the age of the community's population. Additionally, the formula used to designate primary care HPSAs does not take into account the availability of additional primary care services provided by Nurse Practitioners and Physician Assistants in an area. Other sources describing primary care supply use other ratios; for example, a ratio of 1 physician to 2,000 population. To meet this ratio, approximately 16,000 more primary care physicians would need to be added to the current supply in HPSAs.

There are currently approximately 4,900 Dental HPSAs. Dental HPSAs are based on a dentist to population ratio of 1:5,000. In other words, when there are 5,000 or more people per dentist, an area is eligible to be designated as a dental HPSA. Applying this formula, it would take approximately 7,300 additional dentists to eliminate the current dental HPSA designations.

There are currently approximately 4,000 Mental Health HPSAs. Mental Health HPSAs are based on a psychiatrist to population ratio of 1:30,000. In other words, when there are 30,000 or more people per psychiatrist, an area is eligible to be designated as a mental health HPSA. Applying this formula, it would take approximately 2,800 additional psychiatrists to eliminate the current mental health HPSA designations. Additionally while the regulations allow mental health HPSA designations to be based either on psychiatrist to population ratio or core mental health provider to population ratio, most mental health HPSA designations are currently based on the psychiatrists only to population ratio. Core mental health providers include psychiatrists, clinical psychologists, clinical social workers, psychiatric nurse specialists, and marriage and family therapists.

Medically Underserved Areas (MUAs) may be a whole county or a group of contiguous counties, a group of county or civil divisions or a group of urban census tracts in which residents have a shortage of personal health services.

Medically Underserved Populations (MUPs) may include groups of persons who face economic, cultural or linguistic barriers to health care.